DGA-6000 ULTRA-HD VIDEO GENERATOR / ANALYZER USER MANUAL
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Using the 3D Crosstalk Pattern
In the Generator menu select the 3D Mode sub-menu’s Crosstalk item to produce a special test pattern to
measure the amount of 3D crosstalk between left eye and right eye images as seen through 3D glasses.
The amount of crosstalk is a function of both the 3D display and its 3D glasses. A menu is displayed below
the special Crosstalk test pattern that includes the following items and the calculated Xtalk % value:
Level
(xx)%
Xtalk x.xx%
Color
(Gray, Red, Green, Blue)
Mode
(L to R, R to L)
Window
(Match, 100%, Xtalk)
Gamma
(1.5-3.0)
Select the menu items with the Up/Down keys. Select the item values with the Left/Right keys. Exit the
Crosstalk Pattern/Menu by pressing the Menu key.
The special Crosstalk pattern is a 100% signal level Window Frame surrounding two 0% (black) windows
(“boxes”). The Window Frame is produced in only the left or right eye’s image (e.g left eye). But because of
crosstalk the Window Frame appears at a lower brightness in the opposite eye’s image (e.g. right eye).
Level
%
- While looking through only one eye (e.g. right eye) with 3D glasses, the video signal
Level
and
therefore the corresponding brightness of the boxes in that eye’s image (e.g. right eye) can be adjusted until
the box brightness matches the Window Frame’s crosstalk brightness. Hence, the Equivalent Crosstalk
Level (ECL) can be determined for Left to Right Crosstalk.
Mode
- We can also reverse the procedure (
L to R, R to L
) to determine the ECL for Right to Left Crosstalk.
Differences between Left to Right ECL and Right to Left ECL can be expected because of differences in the
3D glasses left eye and right eye extinction ratios, and other effects of the display technology.
Color
- It can be somewhat difficult to determine the best brightness match because of grayscale color shifts
between the Window Frame crosstalk and the boxes. Crosstalk may also vary with spectral color. For those
reasons the test pattern color can be set to
Gray, Red, Green, or Blue
.
Gamma
- While ECL can be useful as a simple metric for 3D crosstalk, it doesn’t express crosstalk as a
percentage of image brightness because it doesn’t take into account display gamma. Displays with the same
ECL will have different percentage amounts of visible crosstalk if they have different gamma curves. In
addition the ECL expressed as a percentage of 100% signal level is numerically large and somewhat
misleadingly. For instance, if the ECL is 20%, the actual Crosstalk luminance percentage (Xtalk %) is 2.9%
for a display with a gamma of 2.2. Therefore, the Xtalk % is calculated based on display gamma, which can
be selected by the user.
Window
– The
Match
setting is used to display the Window Frame test pattern, which when matched
produces the calculated Xtalk % based on the display’s gamma value. However, the display gamma at the
crosstalk Level may not be accurately known, and the user may wish to measure the Xtalk % directly. The
100%
and
Xtalk
settings display the 100% video level and the matching Xtalk Level as full windows so the
luminance (Y) can be measured directly from the display. Xtalk % = Y(Xtalk)/Y(100%).
Note: The
100%
and
Xtalk
windows are displayed as left and right eye images respectively for
the L to R Mode (and visa-versa for the R to L Mode) to produce the same luminance levels
used in the
Match
mode. At low frame rates (e.g. 1080p24) the increased flicker may create
problems for some luminance measurement devices. You can reduce the flicker and double
the light output for LCD or DLP displays by displaying the
100%
and
Xtalk
windows in both
left and right eye images by pressing the Func - Y/C key sequence after selecting
100%
and
Xtalk
. However, the increased light output could produce limiting on the 100% window in
some 3D plasma display panels
